Laundry appliance

ABSTRACT

A laundry appliance includes a cabinet or surround structure with an attachment for a removable front panel and a removable front panel for attachment to the cabinet. The appliance is a drum and a drum support structure supporting the drum for rotation. There is a movement interface between the drum support structure and the cabinet or surround structure, allowing the drum support structure to move between an operating condition within the cabinet and a maintenance condition wherein the drum and drum support structure are at least substantially disposed outside the envelope defined by the cabinet. In the operating condition the drum and support structure are hidden behind the removable front panel. They may be moved out to the maintenance condition after removal of the front panel.

This application is a divisional application of U.S. patent applicationSer. No. 10/963,395 filed on Oct. 12, 2004, which is a divisionalapplication of PCT/NZ03/00065 which has an international filing date ofApr. 10, 2003 and was published in English on Oct. 23, 2003 underInternational Publication Number WO 03/087459. The disclosure of U.S.patent application Ser. No. 10/963,395 is herein incorporated byreference in its entirety.

BACKGROUND TO THE INVENTION

1. Field of the Invention

The present invention relates to laundry appliances and in particularconsumer laundry appliances for the drying of damp textile articles,such as items of clothing, towels and bed linen.

2. Summary of the Prior Art

Prior art clothes drying machines are generally of a type having arotatable metal drum supported within a rectangular cabinet. Therotatable drum includes an open end facing the front of the cabinet anda substantially closed end at the rear of the cabinet. Access is gainedto the open end of the drum by opening a door or hatch on the front faceof the cabinet.

The prior art clothes dryer has a significant ergonomic disadvantage toa top loading laundry appliance. It is a particular disadvantage whenwashing has to be transferred from a top loading clothes washing machineto a front loading clothes dryer.

U.S. Pat. No. 3,514,867 describes a drum type clothes dryer including abelt tensioning arrangement enabling reversal.

JP 2-274294 describes an automatic door opening and closing arrangementfor a rotary drum which requires stopping the drum at a rotary positionfor operating a door stopper provided on the drum door. Operation of thedoor stopper into an engagement released state also brings the drum doorinto a non-movable state relative to the cabinet.

WO 0028127 describes a laundry appliance including a rotatingcylindrical drum with a hatch forming part of the cylindrical surface.The drum is stopped to allow disengagement of the hatch from the drumand engagement relative to the cabinet at the commencement of an openingoperation. It is also stopped for the reversed process at the end of aclosing operation.

U.S. Pat. No. 5,678,430 describes a top loading automatic washer withthe drum provided to rotate on a horizontal axis. The laundry carryingdrum has a hinged opening and is retained within a water collection tubwith a spring loaded flexible sliding tub door.

EP 483909 describes a device for halting the drum of a top loadinghorizontal axis laundry machine in a loading and unloading position.

FR 2478151 describes a drum and hatch construction for a top loadinghorizontal axis washing machine.

WO 00/28126 describes a top loading horizontal axis washing machinewherein user access to the drum is provided by moving the drum at leastpartially out of a surrounding cabinet to expose an access opening.Rocking, pivoting and sliding arrangements are described.

U.S. Pat. No. 4,262,870 describes a retractable self levelling assemblyfor supporting a laundry appliance. The assembly has two spaced apartupwardly and outwardly angled slots for slidably receiving pins whichconnect supporting feet to opposite ends of an adjustable tension bar.

U.S. Pat. No. 4,949,923 describes a self levelling assembly for anappliance with legs slidably received through channels for verticalmovement. Each leg is provided with outwardly extending pins engagedwithin upwardly converging slots of a stabiliser bar.

U.S. Pat. No. 3,954,241 describes a self adjusting levelling assemblyfor an appliance with includes a pair of mounting brackets each providedwith a vertically shiftable, floor engaging leg member. The leg membersare interconnected by a cable such that they are free to shiftvertically relative to their corresponding brackets in a reciprocalrelationship when not supporting a normal proportional share of theweight of the appliance.

U.S. Pat. No. 4,770,275 describes a leveler for a ladder which has apair of sliding legs telescopically engaged in respect of upright tubes.A wire rope is fixed to upper regions of the legs and extends betweenthe tubes. The wire is engaged with a support guide fixed relative tothe ladder structure.

U.S. Pat. No. 3,991,962 describes a self levelling mechanism for anappliance cabinet which includes a polypropylene foot at each corner ofthe cabinet. Each foot is interconnected by a continuous cable forvertical movement in unison relative to the cabinet and to each other. Alocking wedge is provided for each foot for locking each foot in fixedrelation with the cabinet.

WO 95/08016 describes a bulk lint collector for a clothes dryer. Anannular lint filter rotating with the dryer drum extends from one end ofthe drum and encircles the dryer door. Lint is collected in a cavity inthe dryer door and removable by removing an outer face panel of thedoor.

SUMMARY OF THE INVENTION

It is an object of the present invention to provide a laundry dryingappliance and or associated parts and or associated methods which atleast go some way towards overcoming disadvantages of the prior art orwhich will at least provide the public with the useful choice.

In a first aspect the invention may broadly be said to consist in alaundry appliance including:

a cabinet, base or surround structure, including an attachment for aremovable front panel,

a removable front panel for attachment to said cabinet, base or surroundstructure,

a drum,

a drum support structure supporting said drum for rotation,

a movement interface between said drum support structure and saidsurround structure, allowing said drum support structure to move betweenan operating condition within said cabinet or surround structure andbehind said removable front panel, and a maintenance condition with saidremovable front panel removed and wherein said drum and said drumsupport structure are at least substantially disposed outside theenvelope defined by said cabinet or surround structure.

In a further aspect the invention may broadly be said to consist in aclothes drying appliance including:

a base structure,

a drum,

a drum support structure supporting said drum for rotation,

a movement interface between said drum support structure and said basestructure,

an outlet duct supported on said drum support structure and including aninlet end connected with an air outlet of said drum and an outlet end,and

an exhaust duct connected with said base structure and including anoutlet port outside said base structure and an inlet port positioned tomate with said outlet of said outlet duct with said drum supportingstructure in an operating position on said base structure.

In a further aspect the invention may broadly be said to consist in aclothes drying appliance including:

a base structure,

a drum,

a drum support structure supporting said drum for rotation about ahorizontal axis,

a movement interface between said drum support structure and said basestructure,

an inlet duct supported on said drum support and including an outlet endconnected with an air inlet of said drum and an inlet end, and

an inlet air heater is fixed to said base structure and includes acowling with an outlet end, said outlet end of said cowling positionedto mate with said inlet of said inlet duct with said drum supportingstructure in an operating position on said base structure.

To those skilled in the art to which the invention relates, many changesin construction and widely differing embodiments and applications of theinvention will suggest themselves without departing from the scope ofthe invention as defined in the appended claims. The disclosures and thedescriptions herein are purely illustrative and are not intended to bein any sense limiting.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a cross sectional side elevation (from the right side) througha clothes dryer according to the preferred embodiment of the presentinvention.

FIG. 2 is a cross sectional front elevation through a clothes dryeraccording to the preferred embodiment of the present invention.

FIG. 3 is an isometric view assembly drawing, from the rear, showing thedrum, and hatch engagement mechanism of the dryer of FIG. 1.

FIG. 3A is an enlarged view of the region of FIG. 3 including the hatch.

FIG. 3B is an enlarged view of the region of FIG. 3 including the hatchengaging member door and side housings.

FIG. 4 is an enlarged view of the region of FIG. 2 including the airintake end of the drum.

FIG. 4A is an enlarged view of the bearing region of FIG. 4.

FIG. 5 is an enlarged view of the region of FIG. 2 including the airoutlet end of the drum.

FIG. 5A is an enlarged view of the upper end of the lint filter housingand bearing region of FIG. 5.

FIG. 5B is an enlarged view of the lower end of the lint filter housingand bearing region of FIG. 5.

FIG. 6 is a cross sectional side elevation (from the right side) througha clothes dryer according to the preferred embodiment of the presentinvention, shown in an operating configuration with the drum fullyclosed.

FIG. 7 is a cross sectional side elevation (from the left side) througha clothes dryer according to the preferred embodiment of the presentinvention, the position corresponding to the start of a drum openingoperation or the conclusion of a drum closing operation.

FIG. 8 is cross a sectional side elevation (from the left side) througha clothes dryer according to the preferred embodiment of the presentinvention, the position corresponding to during a drum openingoperation.

FIG. 9 is a cross sectional side elevation (from the right side) througha clothes dryer according to the preferred embodiment of the presentinvention, shown in an operating configuration with the drum fully open.

FIGS. 10 and 11 are side elevations of a drum hatch engaging assembly,with partial cutaway revealing an actuator mechanism. FIG. 10 shows thedrum hatch engaging member in a non-engaging position. FIG. 11 shows thedrum hatch engaging member in an engaging position.

FIG. 12 is a block diagram of the control system of the dryer accordingto the preferred embodiment of the present invention.

FIG. 13A is an enlarged view of the front foot region of FIG. 1.

FIG. 13B is an enlarged view of the right side foot region of FIG. 2.

FIG. 14 is an enlarged view of the upper rear region of FIG. 1 showingthe joining between the rear edge of the top deck and the upper edge ofthe rear face of the cabinet.

FIG. 15 is a flow diagram showing the sequence of operations of the drumopening method according to one aspect of the present invention.

FIG. 16 is a flow diagram showing the sequence of operations of the drumclosing method according to one aspect of the present invention.

FIG. 17 a to 17 c are a flow diagram showing the sequence of operationsof an reinitialization procedure according to one aspect of the presentinvention.

FIG. 18 is a view of the main drive assembly, including motor andhousing, belt tensioner, fan and fan housing, all assembled to a sidechassis panel and cross rails, viewed from below and to the rear, andwithout other components shown.

FIG. 19 is an assembly drawing of the belt tensioner assembly.

FIG. 20 a is a side elevation of the belt tensioner assembly of FIG. 18,as assembled and showing the pulley carrier in a position of maximumbelt take up.

FIG. 20 b is a side elevation of the belt tensioner assembly of FIG. 18,as assembled and showing the pulley carrier in a position of minimumbelt take up.

FIG. 21 is a view looking into the belt tensioner assembly, as assembledadjacent the motor support bracket, looking from above.

FIG. 22 is a cross section through the drum drive assembly includingbelt tensioner and drive motor and through the exhaust outlet duct, fanand fan housing.

FIG. 23 is a cross sectional side elevation of the portion of themachine including the fan, fan housing and exhaust outlet port.

FIG. 24 is a cross sectional front elevation of the portion of the lowerleft side of the machine showing the heater and heater housing and itsjuxtaposition with the hot air inlet duct opening in an operatingposition.

FIG. 25 is a view of a rear foot arrangement according to an alternativeembodiment which incorporates a self levelling mechanism governed by arestraining band.

FIG. 26 is an assembly drawing of the self levelling foot arrangement ofFIG. 25.

FIG. 27 is a cross section of the self levelling foot arrangement ofFIG. 25 taken along a line coaxial with the restraining band.

FIG. 28 is a view of a front foot according to an alternativeembodiment, wherein the lower edge of the supporting side panel is fixedto a plastic stiffening rail. The stiffening rail incorporates bearingfeatures for providing pivoting action over the front foot.

FIG. 29 is a side elevation of an alternative belt tensioner, generallysimilar to, but simpler than the belt tensioner of FIGS. 19 to 22. Thebelt tensioner of FIG. 29 is particularly suitable where the drive motorcan be controlled to provide lower shock loads during reversal.

FIG. 30 is an assembly drawing of the belt tensioner of FIG. 29.

FIG. 31 is a view of one end of a drum lid leading edge bracket,according to one preferred embodiment which includes a first labyrintharrangement.

FIG. 32 is a view of an edge component for connecting with the edge ofthe drum skin to meet the leading edge of the lid. The edge componentincludes a complementary labyrinth arrangement for engaging with thelabyrinth arrangement of the member of FIG. 31.

FIG. 33 is a cross section showing connection of the leading edgebracket of FIG. 31 to the leading edge of the drum lid and theconnection of the edge component of FIG. 32 to the corresponding edge ofthe drum skin and to its respective vane. FIG. 33 illustrates therequirement for complete engagement of the labyrinth arrangements forthe lid to fully close.

FIG. 33 a is a cross section showing the parts depicted in FIG. 33 in aposition retained open by an obstruction interposed between the closingedges. FIG. 33 a also includes the drum hatch track 109 and hatchengaging member 300, illustrating that incomplete closure of the drumhatch maintains connection between the drum hatch and the cabinet.

FIG. 34 is a cross section on a radial plane showing a peripheralportion of a drum end, with a drum end support member extendingtherefrom. The drum end support member includes an inwardly facingchannel receiving a lateral wing of the lid edge bracket of FIG. 31.

FIG. 35 is a cross section of an alternative outlet duct sealarrangement to that depicted in FIG. 5 and FIGS. 5 a and 5 b.

FIG. 36 is a cross sectional elevation showing an alternative inlet ductseal to that depicted in FIGS. 4 and 4 a.

FIG. 37 is a side elevation of a portion of seal support member of theembodiment of FIG. 36, the portion including a connecting lug extendingfrom the base leg.

FIG. 38 is a cross section through line P-P of the support member ofFIG. 37.

DETAILED DESCRIPTION

Referring to FIGS. 1 and 2, clothes dryer 100 includes a cabinet 101with a top mounted hinging lid 103. The cabinet 101 includes four sidewalls and a floor. Feet 102 are provided on the lower surface of thecabinet 101 to support the cabinet on a supporting surface (eg: floor).A cylindrical drum 104 is supported horizontally within the cabinet 101.The drum 104 includes a sliding hatch opening in its circumferentialskin. The cabinet 101 includes a contoured opening below the lid 103 toin use allow access to the sliding opening of the drum 104.

The drum 104 is supported horizontally within the cabinet 101 from itsends 105 and 110. Each drum end is supported on a chassis. In thepreferred form, and in accordance with one of the inventions herein, thechassis is moved forward from the cabinet 101 with the front of thecabinet removed. In the preferred form described and illustratedmovement of the chassis from the cabinet, together with the drum andother mechanical assemblies, is by a pivoting movement around a pivotaxis adjacent the lower front edge of the cabinet. However othermovement interfaces may be adopted including a rocker interface orsliding interface. For example a rocker interface may take the form oftwo or more downwardly extending curved rockers rolling on appropriatetracks supported on the base panel. A sliding interface may include twoor more supporting telescopic rail supporting the chassis side panels.

Provision of a movement interface to allow for movement of the chassissubassembly out of the cabinet is not a necessary feature of dryersaccording to many of the inventions herein which are equally applicableto dryers where the subassembly is fixed within the cabinet. By way ofexample only, drum opening and closing, mechanical drive, lintcollection, self levelling feet, drum opening and closing and actuationthereof are all aspects of the present dryer which can operateindependently and be incorporated into laundry machines of other typeand form without departing from the intended scope of the respectiveinvention.

The preferred chassis includes a pair of side panels 522 and 622,preferably formed of sheet metal and having rolled edges 400 turnedinwards to form a stiffening flange around its perimeter. Connectingbeams 402, 404 and 406 extend between the chassis side panels 522 and622 below the level of the drum 104. The connecting beams may be formedfrom pressed or folded sheet metal and to a profile having appropriatestiffness properties. The beams may be secured at their ends to thepanels 522 and 622 in any appropriate manner. For example, the foremostbeam 402 may be secured to a turned in flange 401 along the forward edgeof the panels by resistance welding or fasteners, the rear most beam 404may be similarly secured and the intervening beam 406 may be fastened byway of brackets or resistance welded folded tabs.

Referring now also to FIGS. 13A and 13B the lower forward and rearwardcorners of the side chassis sheets are supported. Each corner includesan arcuate bearing edge 412 of part circular contour, which togetherco-operate to locate and support the chassis on upward projections ateach corner of the cabinet. The inwardly turned flange 400 along theedge of each chassis follows this contour, reinforcing the edge andproviding a bearing surface 412. An alternative lower edge arrangementis depicted in FIGS. 25 and 28 and described below.

The four cabinet feet 102 each connect with an adjacent cabinet sidepanel and with the cabinet base panel 413. The feet 102 each include anarrangement 414 of upwardly extending intersecting walls which fitthrough complementary apertures in the turned in lower edges 418 of theside walls 420 and in the base panel 413. The upwardly extendingintersecting walls 414 of each foot 102 include a pair of load bearingwalls 422 aligned parallel to the side walls of the cabinet and whoseside profile can be seen with respect to FIG. 1. The load bearing walls422 include a bearing edge 424 of part circular profile, complimentaryto the part circular bearing surfaces 412 of the side chassis sheets. Anintersecting wall 426 also extends upwardly from each foot 102. Theintersecting wall 426 is aligned parallel with the front face of thecabinet, and therefore perpendicular or at least substantiallyperpendicular to the load bearing walls 422. The intersecting wall 426intersects each load bearing wall 422 near its mid point, buttressingthe load bearing walls 422 against lateral movement. The intersectingwall 426 has an upper edge which is at some points higher than the uppermost parts of the load bearing walls 422. The upper edge of theintersecting wall 426 includes downwardly extending notches 428 to atleast the level of the load bearing edges of the load bearing walls 422,the notches 428 accommodate the inwardly extending flange 400 of therespective chassis side sheet 522 or 622. The notches serve to laterallylocate the respective inwardly turned flange on its respective loadbearing wall.

The particular form of the load bearing surfaces of the foot is notcritical. It is important that the structure is sufficiently strong tolocate the drum support structure in use and during transport. Thearrangement illustrated in FIGS. 13A and 13B includes the pair of spacedapart load bearing walls and is symmetric about a line XX so that thesame part can be used as both left and right feet. While advantageous,this is not necessary. An alternative arrangement with quite differentform, is illustrated in FIGS. 25 to 28. Again the feet are symmetric sothat the same part can be used as either right or left foot but adifferent upstand is used for front feet than for rear feet. Thisarrangement is described in more detail below.

Referring to FIG. 1 and FIG. 13A the front face of the cabinet is formedtogether with the forward portions of the side faces, as a removablefront unit 470. The removable front panel includes lower front footportions 472, whose rearward edges 703 mate with complementary recesses704 in the corresponding front feet 102. The rear edges 474 of the sidewall portions 476 of the front unit 470, and the front edges 478 of theremaining side walls 420 of the cabinet are turned inward as flanges.The turned in flanges 474, 478 butt one another with the front unit 470in place, and are aligned by clips 480 which protrude from one abuttingturned in flange to fit within slots or recesses in the other abuttingturned in flange.

The lower edge of the removable front unit 470 includes a front footportion 472 adjacent each side wall portion thereof. Each front footportion 472 includes a rearwardly extending locking member 700 includinga downwardly extending locking tongue 701. Tongue 701 engages behind afront wall 484 of the respective front foot 102. Lateral rear wall 703of the locking member 700 fits within recesses 704 of the front footload bearing members 422. The upper edge of wall 703 engages under adownwardly facing ledge 490 defining the upper boundary of recess 704.Full engagement of locking member 701 with the foot 102 requires a smallrearward pivoting of the front panel unit 470 about its foot connectionwith the reminder of the cabinet. Disengagement requires a small forwardpivoting. This pivoting may be accomplished by a slight lifting, but isotherwise inhibited by the surface supporting of the front of thecabinet in the vicinity of the join. Slight lifting of the front of thecabinet allows relative pivoting of the feet.

An alternative foot arrangement which includes an alternative form ofsupport of the side chassis panel is illustrated in FIGS. 25 to 28. Inthis arrangement the side chassis is provided with a plastic stiffeningmember 2802 extending along its lower edge. The stiffening member isconnected to the lower edge of the panel, preferably clipping in placeand being further secured by fasteners. The front end of the stiffeningmember 2802 includes a bearing surface 2800 to bear on upstand walls2804. The upstand walls 2804 pass upwardly through an aperture 2810 inbase panel 2808. An engagement extension 2806 passes upward through thebase panel 2808 through another aperture 2812. The engagement extension2808 and the upstand 2804 each extend beyond the bound of the respectiveaperture, in opposite directions. The upstand, including walls 2804 andconnecting lateral bracing, is a separate component from pedestal 2814.Engagement extension 2806 is integral with pedestal 2814.

In connecting the foot to the base panel, the engagement extension 2806is passed through its respective aperture 2812 and the pedestal 2814 ispivoted up to a position against the under face of base panel 2808. Theupstand component is inserted through its aperture 2810 from above andclips into the pedestal component 2814. The leading edge 2816 of theupstand component overhangs the leading edge 2818 of the pedestalcomponent 2814 leaving a recess 2820 for receiving the rearward edges ofthe front foot portions of the removable front unit. Apertures 2820 inthe upper surface of the forward portion of pedestal component 2814 areexposed in the recess 2820 for receiving the locking tongues of theremoval front unit.

The stiffening member 2802 may be attached to the chassis side panels inany convenient fashion. In the form illustrated in FIGS. 25 to 28 itengages with the stiffening member 2802 by a clip arrangement at itsforward end and a fastener at its rearward end, with the side panel andstiffening member each configured so that the side panel bears on thestiffening member along most of its length. At the forward end turned inflange 2840 sits in a trough 2842 behind an upstand 2846. A projection2844 from upstand 2846 extends through an aperture 2848 in the flange2840. Turned in flange 2850 along the lower edge of the side panel sitson a longitudinal rail 2860 of the stiffening member 2802. The flange2850 includes a downwardly turned edge 2852 to provide lateral supportfrom one direction. Relative to the turned down edge 2852 the panelextends behind a forward upstand portion 2854 and a rear upstand portion2856 of the stiffening member 2802, to provide lateral support in theother direction. A turned in flange 2858 on the rearward edge of theside panel sits in a trough 2862 formed by an outward and upwardprojection 2864 of rear upstand 2856. A fastener inserted through hole2866 secures the side panel in position on the stiffening member 2802.

An alternative form of rear foot, illustrated in FIGS. 25 to 27 includesa foot arrangement which provides for automatic levelling. Thearrangement includes a first socket 2500 connected with the cabinetadjacent one side and a second socket connected with the cabinet,adjacent the other side. The first socket is provided in associationwith one rear foot assembly, the second socket is provided associatedwith the other rear foot assembly. A foot 2504 downwardly protrudes fromeach socket. The foot is moveable along an axis into and out of thesocket.

A non-extensile band 2506, fixed at one end 2508 relative to the firstsocket, passes through the first socket, including over an upper bearingsurface 2510 of the first foot. The band passes across the back of thecabinet, adjacent the base panel 2512 and through the second socket,including over an upper bearing surface of the second foot, and is fixedat its other end relative to the second socket.

Each foot 2504 includes a retaining tongue 2514 spaced above the upperbearing surface.

Each socket includes a downward bearing surface 2516 at least in theregion where the band passes out of the respective socket towards theother socket.

Each socket is formed within an internal upstand component 2518, andwithin an external pedestal component 2520. The internal upstandcomponent and the pedestal component are mutually engaged with the basepanel 2512 of said appliance therebetween the foot passes into theupstand member through an aperture in the base panel.

The upstand member includes a band engagement (such as 2522 in FIG. 25,but on the other face) and illustrated in dotted lines in FIG. 27 on theside facing away from the other upstand member. The band engagementengages slots 2524 in the band. When one foot rises, the other drops,the pair being limited by the band. The upper bearing surface of eachfoot and the downward bearing surface 2516 bear on the band in oppositedirections under pressure, preventing movement once the appliance weightis bearing on the feet.

The restraining force applied to each foot by the band is balancedlaterally due to the band passing fully over the foot and being securedto the non-moving structure. Force in a fore and after direction issubstantially balanced due to the use of a non-extensile metal band ofmuch greater width than thickness, as opposed to a wire or other lowaspect ratio alternative. With its width the metal band provides adistributed load on the bearing surfaces of the feet and the sockets soas not to bite into the material from which these surfaces are formed.This allows these components to be manufactured from suitable plastics.

Referring particularly to FIGS. 2 and 8 the dryer console 450, lid 103and a surrounding frame 452 (with tapered access opening) togethercomprise a “top deck” component which is secured to the upper edge 454of the side, rear and front walls of the cabinet. The downwardlyextending peripheral sides 456 of the top deck frame 452 fit over upperedge flanges 458 of the front, side and rear faces of the cabinet. Theseedge flanges are located internally adjacent the peripheral sides 456 ofthe sides and front of the top deck, within tapering slots 460 inlocating members 462 extending transversely from the inner surface 464of the side walls 456. Slots or recesses 466 in the locating members ofthe peripheral side walls of the sides of the top deck also retain theupper edges of the chassis side walls 522 and 622 against lateralmovement.

Referring to FIG. 14 the top deck is maintained in a securedrelationship with the upper edge of the cabinet by a clippingarrangement at its rear side 800. The clipping arrangement comes intoengagement by juxtaposing the clip portions 802 extending from the topdeck rear periphery with lateral slots 804 in the upper edge of thecabinet, with the top deck held in a tilted condition with the frontside higher than the rear side. Subsequently lowering the front edge ofthe top deck brings the top deck into a substantially horizontalorientation with respect to the top edges of the cabinet, with the topedges of the cabinet located within the tapering slots 460 of thelocating members 462 around the sides and front. This maintains thealignment of the top edges of the side walls and retains the upper endof the removable front unit 470 in place against the respective sidewalls. The top deck is secured in this orientation by fastenersconnecting it with the top edge of the cabinet. Preferably thesefasteners connect between the top deck and side housings 304 and 305(see FIGS. 1 and 6 to 9). The side housings 304 and 305 are in turnconnected with the respective chassis side sheets 522 and 622.

For maintenance of the internal dryer components the top deck may bereleased from the upper edge of the cabinet by removing the associatedfastenings. With the top deck released its front portion may be tiltedup to disengage from the upwardly extending flange of the front unit.The front feet engagement may be released by lifting the front portionof the dryer and pivoting the front unit forward. The front unit is nowcompletely removable from the remainder of the cabinet while the topdeck is tilted up. With the front unit removed electrical connectionsbetween the components carried by the supporting chassis and the topdeck may be broken and the entire drum and supporting chassis may bepivoted from the cabinet, with the bearing surfaces of the lower frontcorners of the chassis side walls sliding over the complimentary bearingedges of the upwardly extending front foot bearing walls. The chassiscarries the drum, motor, fan and drive pulley assemblies and presentsthese components to the maintenance person in front of the cabinet. Theheater component, whether gas or electric, is secured to the base paneland is available for inspection and maintenance with the drum andsupporting chassis in its more usual operating position once the frontunit has been removed.

Referring to FIG. 24 the heater component 2400, whether gas or electric,is located at the entrance of an inlet duct 2402 mounted on the basepanel 2404. The inlet duct has an open outlet end 2406 which is alignedwith an inlet opening 2408 of a hot air inlet manifold 2410 with thechassis in its operating position. The hot air inlet manifold is securedto the inlet end tilt out chassis 522.

Referring to FIG. 23, in tilting the chassis and its attendantcomponents into and out of the dryer cabinet a connection is also madeor broken between the squirrel cage fan housing 120 and a cabinet outletport component 1844 which includes the cabinet exhaust outlet 128. Theconstruction and arrangement of this connection is described in moredetail later.

Referring to FIGS. 1 to 3 and 34 the cylindrical drum 104 has a pair ofcircular drum ends and a cylindrical drum skin connecting therebetween.The cylindrical drum skin is made up of a first part-cylindrical skin107 connected permanently with the drum ends 105, 110 and apart-cylindrical drum hatch 108 whose edges slide within a pair ofcircumferential tracks 109 defining the side edges of a drum opening.The permanently connected drum skin portion 107 is supported by vanes106, 186 and 196 as well as by its permanent connection to the drumends. The vanes 106, 186 and 196 each span between the drum ends and areconnected with both the drum ends and the drum skin. The tracks 109 areprovided on a drum end support member 3400 connected to the periphery ofthe drum around that part of the circumference that defines the drumopening. The vanes 186 and 196 connect between the ends of the drum endsupport members. The vanes 186 and 196 form front and back edges of thedrum opening. Together, the vanes 186 and 196 and the drum end supportmembers 3400 define the drum opening.

The drum 104 is rotatably supported within the cabinet 101 by a spindleat one end and an annular bearing surface at the other end.

Referring to FIGS. 4 and 4A the air inlet drum end 110 includes aninwardly domed central portion 500. The central portion 500 includes aplurality of perforations (eg 503) forming air inlet 121. A flat hubportion 504 at the centre of region 500 has a bearing housing 505fastened thereto, for example by rivets 506. A spherical bush 510 issecured within the bearing housing 504 by a thin metal spring cover 515secured to the bearing housing 504 by the fasteners 506.

The hot air inlet manifold 2410 is secured to the inlet end tilt outchassis 522. The hot air inlet manifold comprises an inner side pressedplate 520 and an outer side pressed plate 521, secured together and tothe chassis 522 around the perimeter 531. The perimeter may be securedtogether and to the chassis 522 for example by fasteners or resistancewelding. The inner side plate 520 includes hot gases outlet openings 523which are adjacent the perforated central portion 500 of drum end 110when assembled. Openings 523, 524 are spaced around a central hubportion 535 of the plate 520, leaving spokes intact supporting thecentral hub region 535.

The outer plate 521 includes a depressed central region 530 with anaperture 540 therethrough. The depressed region 530 accommodates thehead of a bolt 508 when assembled. The inner plate 520 includes anaperture 541 aligned with aperture 540 of outer plate 521. A compressiontube 536 is located between the inner and outer plates 520, 521 tomaintain the separation between the plates 520 and 521 in the vicinityof apertures 541 and 540 respectively. A bearing shaft 511 has alocating spigot 555 fitted within compression tube 536 through aperture541. The bearing shaft includes a thrust receiving flange 550 locatedagainst the outer surface of central portion 535 of the inner plate 520.An outer end face of the spherical drum bearing 510 bears against theother side of thrust flange 550. The bearing shaft 511 includes a stubshaft 560 extending into the drum. The stub shaft 560 fits within aninner bore of the spherical bearing 510.

The bearing shaft 511 includes a central axial bore 561 for receivingbolts 508 and 562 which complete the assembly. Bolt 508 passes throughaperture 540 and the bore of the compression tube 536 to be securedwithin one end of the central bore 562 of bearing shaft 511. This leavesthe stub shaft protruding from the inner sheet 520 of the hot gasesmanifold. With the spherical bearing 510 fitted over the stub shaft 560a protective cap 563 is secured to the end of stub shaft 560 by a bolt562. The protective cap 563 covers the flat hub region of the drum endand associated bearing holder 505 and fasteners 506. The bolt 562secures against a flat and central hub of the cover 563. The flat andcentral hub of cover 563 extends beyond the end face of the stub shaft560 to retain the spherical bearing 510 on the stub shaft.

An annular seal is created between the drum end and the inner plate 520of the hot gases inlet manifold by an annular seal 525 located about thecircumference of the inlet openings 523, 524. The soft felt seal 525 isfixed to the drum facing surface of inner plate 520. The drum end 110has an inwardly dished ring 501 concentrically outside the dishedcentral region 500, leaving an outwardly facing annular ridge 526therebetween. The outwardly facing annular ridge 526 presses into thefelt seal 525 to provide an annular seal between the manifold and thedrum end 110.

According to an alternative embodiment illustrated in FIGS. 36 to 38 theannular sliding seal at the drum inlet includes a resilient elastomericsupport member 3600. The support member 3600 is substantially constantcross section having a base leg 3602 and a flexion leg 3604. A feltstrip 3606 is secured to the flexion leg 3604 and the base leg 3602 isconnected with the inlet duct. In place such as illustrated in FIG. 36,the flexion leg 3604 is contorted from a relaxed position (illustratedin FIG. 38), biasing the felt strip against the drum end surface.

The resilient member 3600 includes protruding lugs 3608, which securethe base leg 3602 to the inlet duct by extending through apertures in asupporting panel of the inlet duct. The support member may bemanufactured by extruding a constant cross section profile including theprofile of protruding lug 3608, and removing longitudinal sections ofthe lug portion of the profile to leave protruding lugs 3608 atintervals along the strip. The strip may be extruded from knownelastomers, such as Silicone.

Support of the drum at its outlet end and further detail of the drum airoutlet can be seen with reference to FIGS. 1, 5A and 5B. An alternativeseal arrangement illustrated in FIG. 35 is also described. The drum end105 includes a domed annular cover 165 secured thereto. A stationarycentral hub 131 is secured to the outlet end chassis 622. The centralhub 131 has fore and aft perforated regions 122, and a central lintcollecting container 130, removable from within the drum.

The lint collecting container 130 preferably includes an upper portion650 and a lower portion 651. The upper portion 650 includes a handleelement 652 moulded therein. The lower portion 651 is preferably formedof a clear or see through plastic material. The lower portion 651includes a locating groove 653 to engage with a retaining ridge 654 of ahousing 655 when in place. The upper portion 650 is held in place in thehousing 655 by a resilient engagement of detents 660 in its lateral sidewalls 661 with cooperating protrusions in the housing.

The lint collector 130 is open at its upper end to receive lint peeledfrom an annular lint receiving surface 123 by a fixed position scraper662. Lint falls from scraper 662 through the upper opening of the lintcollector 130.

The annular lint receiving surface 123 extends axially from the outerface of domed ring 165 at its inner edge, and rotates with the drum. Thelint receiving surface 123 is supported on a ladder frame 670 which hasa pair of spaced apart ring members with laterally extending ringsspanning therebetween at intervals around its circumference. The form ofsupporting structure 670 is illustrated in FIG. 3. One ring member isfixed to the outer facing surface of domed cover 165. This may be, forexample, by adhesive by plastic welding, or by fastening with anysuitable fastener.

A pair of horizontal electrodes 683 are also fixed with the stationarycentral portion 131. The electrodes 683 are utilised in the dryercontroller for sensing conductivity of the clothes load, and thereby theassociated moisture content.

The annular lint filter 123 surrounds the stationary portion 131, and inturn is surrounded by an exhaust gases outlet manifold housing 603. Theexhaust gases outlet manifold housing 603 is fixed to the inner face ofthe outlet end chassis 622 by suitable fasteners. The manifold housing603 may for example comprise a plastic moulding, which forms an annularmanifold chamber 605 in combination with the chassis 622. The annularchamber 605 exits to an outlet duct 606 at its lower end which in turnleads to a lateral outlet duct 124 connected with the fan housing 120.

FIGS. 5A and 5B are blown up views of regions of FIG. 5 showing regionsof that cross section including detail of the annular supportingmechanism of the drum. The supporting mechanism is annular and thereforethe main supporting details in FIG. 5A are mirrored in FIG. 5B.

In FIG. 5A it can be seen that the annular lint filter 123 is secured tothe air outlet end of the drum. In particular the inner ring member 721is clipped in place against the inwardly dished end facia 165 by aseries of clips on an annular wall 727 extending from the outer face ofthe fixture 165. Such connection may alternatively or in addition bemade by suitable fasteners, adhesives or plastic welding or the partsmight be integrally formed. The stainless steel drum end 726 includes anannular inward step 730 between an outer planar portion and an innerplanar portion, the inner planar portion comprising an annular flange750 extending radially inwardly. The annular step 730 forms anessentially cylindrical portion.

The annular manifold 605 is enclosed between the manifold housing 603and a manifold housing supporting part 741 fixed to the chassis plate622. The manifold housing 603 includes a generally cylindrical portion751 whose outer surface is generally parallel with the inner surface ofcylindrical portion 730 of stainless steel drum end 726. The generallycylindrical portion 751 of the manifold housing 603 has a radiallyinwardly extending flange 752 extending from its open end, principallyproviding reinforcement and rigidly to the open end. The generallycylindrical portion 751 includes a plurality of receiving slots 753,extending from its corner with the flange 752, toward the supportingmember 741. The slots 753 are spaced around the circumference of thecylindrical portion 751 and each receive a plastic bearing insert 681.The plastic bearing inserts 681 may be formed from any suitable hardwearing low friction material, for example TEFLON impregnatedpolyethylene.

An annular sealing strip 680 is also provided in the space between thecylindrical portion 730 of the drum end 726 and the cylindrical portion751 of the housing 603. The sealing strip 680 may for example be a feltstrip adhered to the outer surface of the cylindrical portion 751 of thehousing 603, typically partially compressed to fit in the space betweenthe two surfaces.

The plastic bearing inserts 681 preferably extend beyond the face of theflange 752 to at least partially butt the corner between cylindricalportion 730 and inwardly turned flange 750 of the drum end 726 and/orthe face of the flange 750. The inserts 681 thus provide both radial andthrust bearing surfaces for the drum end against the perimeter of theoutlet manifold housing 603.

An additional annular seal 682 is provided between the outer ring member720 of the lint filter 123 and the housing supporting member 741. Thehousing supporting member 741 includes an annular inward step forming asubstantially cylindrical radially outwardly facing surface 740, facingthe radially inwardly facing surface 725 of the ring member 720. Theannular seal 682, for example, a felt strip, is secured to the face 725of ring member, for example by an adhesive. The strip is preferablylightly compressed in fitting between the surfaces 725 and 740.

According to an alternative form illustrated in FIG. 35 the sliding sealbetween the drum end and the outlet duct and/or the filter screen andthe outlet duct, comprises a felt strip 3500 connected to a plastic bead3502. The plastic bead 3502 is engaged in a retainer channel 3504 or3506.

The retainer channel 3504 for the seal between the drum end and the ductis located in the outer face of the outlet duct. The retainer channel3506 for the seal between the filter screen and the outlet duct islocated in annular support member 3510 of the filter screen.

The retainer channel 3504 is located so that the felt strip of the sealbetween the drum end and the outlet duct fits within the space betweenan annular corner 3520 of said outlet duct and an annular corner 3522 ofthe drum end and extends around this corner.

The annular manifold chamber 605 is thus defined by fixed componentscarried by the chassis 622 (the manifold housing 603 and manifoldhousing supporting member 741) and rotating components of the drum end(including lint filter 123 with associated supporting structure, facia165 and drum end 726, with the seal being maintained between thestationary and rotating components by annular seals 680 and 682. Thelint collecting container 130 and perforated air inlet panel 131 andassociated supporting assemblies are in effect disposed within the drum,backing on to the manifold supporting member 741 and surrounded by thelint filter 123.

Referring to FIGS. 1, 2 and 18 to 21 a motor 1800 drives rotation of thedrum 104 via a belt and pulley reduction drive. The motor 1800 may be astandard induction motor with a driven shaft projecting from both ends.A drive pulley 1802 for driving rotation of the drum 104 is connected toone projecting end 1804 of the drive motor shaft. The drive belt 1810passes around the drive pulley 1802 and around the drum 104 adjacent oneend. A squirrel cage fan 1806 is connected to the other projecting endof the drive motor shaft for producing a drying air flow through thedrum 104. The drying air flow through drum 104 is produced by thesquirrel cage fan 1806 rotating within fan lousing 120 to draw airsequentially through the intake and heating duct, the drum inlet 121 (ondrum end 110), the drum outlet 122 (on drum end 105), the annular lintfilter 123 and the outlet duct 606 and lateral duct 124, and to exhaustthe air through an exhaust port 128 at the rear of the cabinet 101.

A heater is located in the air inlet duct. The heater may compriseeither a gas heater arrangement or an electrical heating coilarrangement, both of known type. Operation of the heating unit, whetherof gas or electric type is controlled by an electronic control module139.

Electronic control module 139 also controls the energisation of thedrive motor for the drum and fan as will be described later in thisspecification. Motor speed control may, for example, be by PWM dutycycle control, on mains supply or by inverter frequency control of arectified supply. The latter is preferred due to improved speed controland lower belt loads during reversal.

Air exiting drum 104 passes through the annular lint filter screen 123of substantially cylindrical form and extending from the drum end 105.The air flow passes outward through the lint filter screen 123,depositing a lint layer on the internal surface of the screen. Themanifold housing support 741 supports the perforated air outlet facia122 which in turn supports the bulk lint collecting container 130 withina central aperture 131 of drum end 105. A scraper which forms part ofbulk lint collecting container 130 (or alternatively supported directlyby the air outlet duct) peels entrained lint from the surface of lintcollecting screen 123 to fall through an opening in the top end ofcontainer 130 and collect within the container 130. The container 130 isremovable from within the drum for emptying.

The air outlet end arrangement as described is the preferred form.However a comparatively simple conventional configuration might also beadopted.

For example a bearing assembly similar to that at the air inlet end ofthe drum could be used, with a lint filter screen provided covering theperforated air outlet, a protecting cover to guard the filter screenfrom the tumbling dryer load.

Motor Drive Assembly and Belt Tensioner

One preferred motor drive assembly and belt tensioner will be describedwith reference to FIGS. 1 and 18 to 22. Another preferred belt tensionerof broadly similar design is illustrated in FIGS. 29 and 30 and alsodescribed. The particular motor drive assembly, so far as it includesthe mounting arrangement, and the particular preferred belt tensionersand mounting arrangements for the belt tensioner are described in thecontext of the preferred mechanical arrangement for the drying machinewhere the machine internals are movable out of the basic cabinet as acomplete or nearly complete unit. Aspects of the motor drive assemblyand the mounting arrangement for the belt tensioner could varyconsiderably while remaining within the intended scope of aspects of thepresent invention, particularly but not solely in embodiments of thelaundry appliance that do not include this moving subassembly feature.In that case mounting the motor drive assembly directly from the basepanel, and provision of idler pulleys directly and independently sprungfrom the side panel or base panel may suffice, although a simplifiedbelt tensioner along the lines of those thereinafter described couldstill be used to advantage.

Referring to FIGS. 18 and 22 the main drive motor 1800 and squirrel cagefan housing 120 are supported by a motor support bracket 1812 which inturn connects with connecting beams 406 and 404. The motor supportbracket 1812 includes a frame 1814 and a pair of side members 1816 and1818 each including a plurality of spaced apart clips 1820 which engagewith turned over flanges of the respective connecting beams. The frame1814 includes a motor well 1826 and the upper half 1828 (see FIG. 1) offan housing 120.

The motor well 1826 preferably includes an aperture 1830 to elevate heatbuild up from the motor 1800. The motor 1800 includes a resilient mount1831 at each end with the respective shaft portion 1833 and 1835 passingout through the resilient mount. The resilient mounts are connected withthe motor housing and are non-rotating relative to the housing. Themotor well 1826 has a pair of end walls 1832. Each end wall includes asemi-circular recess 8037, 1839 for receiving the respective resilientmounting of the motor. Motor mounting is completed by securing amounting cover 1834 over each of the resilient mountings. The mountingcovers 1834 have a second substantially semi circular recess such thatwith the covers 1834 engaged and secured with the end walls 1832 theresilient mountings of the motor are pressed and held by the semicircular recesses.

Prior to assembly of the motor to the motor support bracket 1812 a fan1806 is secured to one projecting shaft 1833 and a drive pulley to theother shaft 1835. Once the motor is assembled with the motor bracket1812, a lower half 1836 of fan housing 120 is secured to the motorbracket 1812 to substantially enclose the squirrel cage fan 1806.Referring to FIG. 23 the lower fan housing 1836 includes an outletopening 1838 which is adjacent the cabinet outlet port 128 with thechassis rocked back in its operating position. The opening 1838 issurrounded by a flange 1840 with an upstand wall 1842 adjacent the lowerperimeter of the opening 1838. The flange 1840 and upstand wall 1842mate against an annular seal 1845 fitted to a complimentary surroundingflange 1843 of an outlet port component 1844 (FIG. 1). The annular sealmay for example be a felt strip or similar soft and resilient material.The outlet port component 1844 includes an opening therethrough leadingto outlet port 128 extending from its rear side.

With the supporting chassis rocked back into the cabinet the rearwardand downward pressing of the combination of flange 1840 and upstand wall1842 improves the sealing around the lower edge of opening 1838. Acomplimentary upstand wall 1847 from the surrounding flange of outletport component 1844 partly extends to opening 1838 to improve thesealing of the upper portion of the connection. In addition to sealingagainst the resilient sealing material this arrangement further providesan overlapping seal across the connection between the lower fan housing1836 and the outlet port component 1844.

A belt tensioner 1850 is secured to the connecting beams 404 and 406 inproximity with the drive pulley 1802.

The construction of one preferred embodiment the belt tensioner isparticularly illustrated in FIGS. 19, 20 a and 20 b and FIG. 21. Theconstruction of an alternative embodiment is illustrated in FIGS. 29 and30.

Referring to FIGS. 19, 20 a, 20 b, and 21 the belt tensioner includes apair of tensioner pulleys supported to have a fixed separation distancebetween their rotation axis and supported to be located with a bight ofthe drive belt passing therebetween. The bight 1851 of the drive beltpasses between the tensioner of pulleys and around the main drive pulley1802. The main drive pulley may optionally be machined on to the motorshaft. The support assembly for the tensioner pulleys presses thetensioner pulleys away from the drive pulley (toward the drum) 1802 in adirection to lengthen the bight passing therebetween, thereby promotinga longer overall belt path, but, being constrained by the drive belt,achieving instead a tensioning effect on the drive belt. The separationof the belt tensioner pulley running surfaces is also maintained to intuin maintain a minimum angle of wrap of the drive belt around the drivepulley 1802.

On a machine without a subassembly capable of moving out of the interiorof the cabinet carrying the drive system, these tensioner pulleys may besupported on a frame of any particular shape or design, supported fromthe cabinet base or walls or any drum supporting framework, and providedwith a biasing agent to urge the pulleys toward the drum. For examplethe support may be by way of a spring loaded telescoping strut.

In the preferred construction of the drive belt tensioner the belttensioner pulleys 1860 and 1862 are supported by a yoke component 1864on shafts 1866 and 1868 respectively. The shafts 1866 and 1868 arelocated in receiving notches 1870 of the yoke 1864. The receivingnotches 1870 include a tapering entry portion and part circularreceiving portion. The shaft 1866 and 1868 pass a neck between the entryportion and receiving portion during assembly, to locate in thereceiving portion and be captured there by the neck. Heads 1872 of theshafts 1866 and 1868 are captured by hooked protrusions 1874 located onthe yoke 1864 adjacent each receiving notch 1870. The hooked protrusions1874 prevent removal of shafts 1866 and 1868 from the yoke 1864 in anaxial direction. Preferably the shaft heads are non-circular andcooperate with the protrusions 184 to prevent rotation relative to theyoke 164 which might otherwise induce wear in the receiving notches 1870eventually leading to release of the shafts.

The yoke 1864 is supported from a belt tensioner bracket 1880 to bereciprocable relative to the diameter of the drive pulley 1802 androtatable about the drive pulley 1802. A biasing agent is providedbetween the belt tensioner bracket 1880 and the yoke 1864 to press theyoke 1864 toward the drive pulley 1802. The biasing agent 1882 comprisesa carrier 1884 which fits into a cavity 1885 (shown in dot-dash brokenlines in FIGS. 20 a and 20 b) of yoke 1864 to be slidable into and outof the cavity 1885. A compression spring 1886 fits within the carrier1884 and within the cavity in the yoke 1864 and operates between theyoke 1864 and the base 1888 of the carrier 1884. On its outer surfacethe base 1888 of carrier 1884 includes a wear resistant shoe 1890. Withthe belt tensioner assembled the shoe 1890 slides on an arcuate slidingtrack 1892 of the belt tensioner bracket 1880. The outer surface of shoe1890 and the sliding surface 1892 are preferably of complimentary formto provide lateral location of the shoe 1890 on the sliding track. Thecomplimentary form may comprise complimentary cross-sectional profilessuch as concave and convex curves or square, trapezoidal or V-shapedridges and channels. Preferably the profile is shallow to discourage thepossibility of a binding engagement occurring between the slidingsurfaces. In the preferred form depicted the profile is a shallowV-shaped channel for the outer surface of the shoe 1890 and acomplimentary shallow V-shaped ridge for the sliding surface 1892 of thebelt tensioning bracket 1880.

A pivotal slidable connection is provided between the yoke 1864 and thebelt tensioner bracket 1880. A centre channel 1894 of yoke 1864 fittingover a central stub 1896 extending off a spanning web 1898 of belttensioner bracket 1880. Web 1898 spans between the arms of bracket 1880.When assembled and in position the drive pulley 1802 of the drive motorprojects into an open cavity 1900 of stub 1896 with the supporting shaftof the motor projecting through a notch 1902 in an end face 1904 of stub1896. The cavity 1900 is open to its upper side such that in use thebelt passing around the drive pulley passes out of the cavity 1900through the open upper side. When assembled a part annular projection1906 from stub 1896 locates against a receiving portion 1908 ofresilient mount housing 1834. This ensures correct location of thepulley 1802 within the cavity 1900 and relative positioning of thepulley 1802 relative to the belt tensioner assembly.

A wear resistant low friction bush 1910 facilitates the pivotalconnection between the yoke 1864 and belt tensioner bracket 1880. Inparticular the bush 1910 has a rotational interface with the stub 1896and a slidable interface with the yoke 1864. The bush 1910 preferablyincludes at least one part frustoconical internal bearing surface 1914matching an exterior part frustoconical surface 1912 of stub 1896. Thebush 1910 further includes a pair of substantially parallel outwardlyfacing bearing surfaces 1918 which ride against inwardly facing bearingsurfaces 1920 of the channel of the channel 1894 ofyoke 1864. The bush1910 includes an extensive notch 1924 in its upper portion to permit thebelt to pass from cavity 1900 of stub 1896 when assembled. The bush 1910includes a thrust flange 1926 which bears against a face of transverseweb 1898 of the belt tensioner bracket when assembled. The thrust flangeprevents the part frustoconical bearing surfaces of the stub 1896 andbush 1910 from binding in use.

Referring now to FIGS. 20 a and 20 b operation of the belt tension isdemonstrated. With a comparatively tight belt, for example a new belt,the yoke 1864 is prevented from significant forward movement toward thedrive pulley 1802 by the tension in belt portions 1934 and 1936 whichpass over the tension of pulleys 1860 and 1862. This is despite thepressing of the spring 1886 of biasing agent 1882. Carrier 1884 isdepressed into the yoke 1864, retaining the spring 1886 in a compressedcondition. This condition is depicted in FIG. 20 b.

The spring 1886 continues to press the yoke 1864 toward the pulley 1802.Accordingly if the belt lengthens through age or wear the yoke 1864 ispressed forward to increase the length of the bight 1398 of the beltwhich passes around the pulley 1802, as is depicted in FIG. 20 a. Thetensioning pulleys continue to press against and tension the drive belt.

As has already been discussed the yoke 1864 is rotatable about the drivepulley 1802 as well as being slidable toward and away from the pulley.Rotation about the pulley 1802 is preferable to account for thediffering belt tensions between the belt portions 1934 and 1936 with thepulley 1802 operating in differing rotational directions. In the FIGS.20 a and 20 b a condition is shown which the yoke 1864 will adopt wherethe pulley is rotating in a clockwise direction as indicated by arrow1940. Rotation in the clockwise direction results in a higher tension inbelt portion 1934 than in belt portion 1936 causing the yoke 1864 toadopt this or a similar rotational position. If the pulley 1802 isrotated in the reverse, anti-clockwise, direction this will cause agreater tension in belt portion 1936 than in belt portion 1934 and willcause the yoke 1864 to rotate as indicated by arrow 1932, with thesliding carrier 1884 sliding across sliding surface 1892 of belttensioner bracket 1880.

Accordingly the preferred belt tensioner

-   -   is easy to install by clipping over the chassis beams,    -   is compact, and rocks out with the chassis, with no connection        to the cabinet or base panel,    -   alters the belt path when the drive changes direction in a way        which limits the maximum loads on the bearing surfaces of the        tensioner pulleys, and    -   provides frictional damping to the drive system, to control        oscillation when changing speed or direction of drum rotation.

In the belt tensioner assembly most components may be formed fromplastic materials. However some parts may be usefully formed from othermaterials. For example shafts 1866 and 1868 may be formed from steel andsliding shoe 1890 may be formed from a sheet metal pressing, for examplefrom brass. Spring 1886 is preferably of conventional form and materialfor coil compression spring. It will be appreciated that other forms ofspring, such as leaf spring or air spring may also be applicable. Givenits function the bush 1910 preferably includes a friction reducingfiller, for example a plastic composition including PTFE. The slidingcarrier 1884 may also be advantageously provided with a similar lowfriction filler. In the motor support assembly, the motor supportbracket 1812, lower fan housing 1836 and resilient support housings 1834may all be moulded from suitable plastic material.

In the alternative embodiment of FIGS. 29 and 30 the biasing agentcomprises a spring 2906 captured between the yoke 2900 and the bracket2902. The yoke and the bracket are preferably provided with springengagement features such as annular upstand 2936 on the bracket. A splitthrough the upstand (and bracket in near vicinity) assists assembly byallowing the upstand to compress to fit within the bore of the spring. Aspigot 2904 extends from the yoke and passes through an aperture in thebracket with generous clearance. The spring provides the yoke withflexibility of position with a limited centering force. This arrangementis suitable for motor arrangements giving low shock loading, such as anelectronically commutated motor driven by a frequency controlledinverter.

Each pulley 2910 rotates on a bearing 2912 on a shaft 2914 supported bythe yoke 2900. Heat dissipating flanges 2920 are connected with eachshaft.

The heat dissipating flanges 2920 comprise a hub shield fitted on theshaft and substantially enclosing the hub region of either side of thepulley but not contacting the pulley. The hub shields, like the shaft,do not rotate and are screwed in place by lugs 2930, which clip overedges 2932 of the yoke. The shields are formed of material of high heatconductivity, preferably pressed sheet aluminum.

Drum Hatch 108

With particular reference to FIGS. 1 to 3 the drum (excluding the hatch)broadly is made up of a pair of circular drum ends 105 and 110 andpart-cylindrical drum skin 107. The drum ends 105 and 110 are connectedwith the part-cylindrical drum skin 107 through a folded rim 150 formedalong either circumferential periphery.

The drum further includes vanes 186 and 196 connected with the edges 160and 151 respectively of the part-cylindrical drum skin defining edges ofthe drum opening. The vanes provide additional rigidity to the drumstructure, supporting the drum skin (and in particular the free edgesthereof). In addition the vanes are sculpted to assist with evendistribution of the laundry load during operation.

The drum end 105 has a double skin in its hub region adjacent the airflow exit and lint collector. The internal face of the air exit and lintcollector is displaced somewhat into the interior cylindrical chamber ofthe drum and is surrounded by inwardly dished facia 165. The outer layer166 of the drum end includes an annular circle of dimples 153, with anon dimpled region 154 at known angular position relative to the drumopening. The region with an absence of dimples is used to detect thedrum rotational position in operation. For locating purposes duringmanufacture, each vane includes an end protrusion 156 protruding throughan aperture 157 in each drum end 105, 110.

Referring to FIG. 3, at the drum opening a pair of side baffles arefixed to the inner facing surfaces of the drum ends at the periphery ofthe drum and extending between the vanes 186 and 196. Each side baffleincludes a tapering internal face and an inwardly facing track 109. Theside baffles are preferably added plastic components and are connectedwith the respective drum ends by appropriate fasteners, such as selfthreading screws.

The drum hatch 108 includes a part cylindrical section 181 of stainlesssteel with opposed side edges 185, a leading edge 182 and a trailingedge 183. The side edges 185 are folded outward over on themselves toprovide a reinforced edge and present a rolled edge to the channels. AnS-bend 184 is formed in the trailing edge 183 of the drum hatch 108. TheS-bend is formed to present both an inward hump and an outward hump atthe trailing edge of the drum hatch 108 across the width of the drumhatch. The internal hump rides over the external surface of thepart-cylindrical drum skin 107 and presents a low friction bearingsurface to the drum skin. The external hump ensures that the cut edge ofthe hatch skin 181 is presented toward the drum rather than away fromthe drum, improving safety during any maintenance or corrective work onthe machine.

The leading edge 182 of the drum hatch 108 is provided with parts of amechanism for enabling the securement of the drum hatch positionrelative to the dryer cabinet. In particular the drum hatch is providedwith a pair of T-shaped pivoting arms 200. The T-shaped pivoting arms200 include transverse catch members 201 and a pivot aim 202 connectingbetween the transverse catch members 201 and the part-cylindrical drumhatch skin 181. The catch members 201 include an axial bore extendingfrom their inner end toward their outer end. A joining rod 203 has itsends fitted within the axial bores 204 of the catch members 201. The rod203 provides a strengthening backbone for the catch members 201 andreduces the degrees of freedom of their movement. The pivot arms 200 areconnected with the drum hatch 108 at their ends away from the catchmembers 201. The pivot arms 202 are secured to a central double leg 233of a flat spring member 230. The double arm 233 resides within a recess213 in the outer face of the pivot arm 202 and is held in place around acentrally located upstand 210 at the head of the recess 213. The doubleleg 233 is connected to a pair of outer side legs 231 of the springmember 230 via a pair of laterally extending torten portions 232. Theouter legs 231 of spring member 230 are clamped between the inner face235 of a hatch edge stiffening plate 220 and the outer surface of thepart-cylindrical drum hatch skin 181. The clamped portions of the springmember 230 may be located within grooves or channels formed in the innerface of the stiffening plate 220.

A stiffening plate 220 is preferably secured to the drum hatch 108. Aleading lip 240 of the stiffening member 220 includes slots or recessesin a back edge thereof and is fitted over forward extending tongues 241of the front edge 182 of drum hatch skin 181. The rear edge of thestiffening member 220 is secured to drum hatch skin 181 by fastenerspassing into securing holes 224 of the stiffening member 220. Thesecuring holes 224 preferably correspond with the apexes of the U-shapedsections formed by (sequentially) each connected outer leg 231, tortenportion 232 and double leg 233 of spring member 230. This providesadditional securement of the spring member 230 in its place between thestiffening member 220 and the drum hatch skin 181.

According to an alternative embodiment of stiffening plate illustratedin FIG. 31, the plate includes a lateral wing 3100 at either end thatslides within the track 109 to reduce any bending load on the edge ofthe hatch.

Referring again to FIG. 3 the flat spring 230 is secured in positionwith the central double leg 233 passing over a neck recess 236 betweenthe screw securing holes 224 to secure on the outer face of the pivotarm 202.

The pivot arm 202 resides within a recess or aperture 221 of thestiffening member 220. The aperture 221 is preferably shaped to matchthe shape of pivot arm 202 to provide a snug location with the pivot arm202 in a first position against the drum hatch skin 181.

The aperture 221 includes a forwardly facing butting face 225 adjacentthe recessed neck 236 and securing holes 224. The butting face 225 buttsagainst a corresponding butting face 211 at the end of pivot arm 202distil from the catch member 201.

The aperture 221 also includes rear facing butting surfaces 222 whichbutt against forward facing butting surfaces 212 of pivot arm 202 withthe pivot arm 202 in its first position. Therefore, at least in itsfirst position, the pivot arm 202 is prevented from significant forwardmovement relative to the stiffening member 220 by butting of the faces222 and 212.

The pivot arms 202 are pivotable about their ends distal from the catch201 to a second condition away from the drum hatch skin 181. In both thefirst and second position the T-shaped pivot member 200 is restrainedfrom rearward movement relative to the stiffening member 220 by buttingof the pivot member butting surface 211 and the stiffening memberbutting surface 225.

Clearly an alternative but less preferred connection between the catchmembers 201 and the drum hatch 181 could include simple hinges fastenedto the drum hatch skin with any appropriate spring mechanism operatingbetween the drum hatch skin and the catch member.

However the presently described mechanism is preferred due itssimplicity of assembly which is now described. The stiffening member 220is fitted to the drum hatch skin 181 by fitting the recesses of lip 240over tongues 241 and inserting fastenings through holes 250 of drumhatch skin 181 to secure through corresponding holes 224 of thestiffening member 220. The T-shaped pivot arms 200 are pre-assembledwith the connecting rod 203. This pivoting assembly may then be securedto the stiffening member 220 by passing the outer legs 231 of the springmembers 230 below the under side of the stiffening member 220 from therearward edge thereof with the u-shaped section 233 pushed into thepivot arm recess 213.

According to an alternative and preferred embodiment illustrated inFIGS. 31 to 33 the drum hatch stiffening member includes a labyrinthformation along its opening edge and the opposed edge of the drumopening includes a complementary labyrinth form, such that, for the drumhatch to fully close the labyrinth forms must engage into one anotherwith close tolerance.

The labyrinthine formation of the stiffening member (FIG. 31) and thelabyrinthine form of the drum opening edge (FIG. 32) includeinterleaving protuberant walls 3102 and 3202 for engagement intocomplementary socket forms 3104 and 3204, of the opposed part.

The walls must fully engage in the sockets, as in FIG. 33, for the lidto fully close. If clothing is trapped in the closure the engagement isprohibited by the pressure of even very thin fabrics which span over themultiple spaces of the sockets.

As illustrated in FIG. 33A, if fabric is interposed in the closing gapwhen the stiffening member comes together with the open drum edgeinitial engagement of the pair of protuberant walls 3202 into therespective sockets 3104 binds and secures the fabric in two spaced apartregions. A bridge of fabric spanning between these regions is trappedover protuberant wall 3102 which is attempting to enter socket 3204.Close tolerancing of protuberant walls 3202 into sockets 3104 can ensurethat this restraining bridge is created even by very thin materials,along the thinnest materials and/or very stretchy materials, such aspantyhose, may still not be sufficient to prevent closure with realistictolerances. However it is also the case that materials which do notprevent closure are generally of insufficient strength to cause damagewithin the machine during operational rotation of the drum and are notgenerally present in valuable garments.

Also as illustrated in FIG. 33A until complete engagement of thecomplementary labyrinth forms the catch members 201 remain trappedwithin the confines of the drum engaging member above the outer surfaceof track 109. Thus the hatch is not released by the drum hatch engagingmember and rotation of the drum is stalled. Preferably the motorcontroller detects cessation of drum rotation, such as by methodsoutlined later in relation to drum opening operations. Preferably thecontroller then reopens the drum by commencing a drum opening rotation,and operates an appropriate user notification.

Drum Hatch Engaging Mechanism

The clothes dryer is provided with a drum hatch engaging mechanismconnected with the cabinet. The mechanism secures the drum hatch againstmovement relative to the housing at the beginning of a drum openingoperation and throughout the period when the drum is open or partiallyopen, and releases the drum hatch at the conclusion of a drum closingoperation. In performing this function the drum hatch engaging mechanismoperates to engage, hold and subsequently release the catch members 201of T-shaped pivot arms 200.

Referring particularly to FIGS. 3 to 3B, 6 to 10 and to FIG. 33A, thedrum hatch engaging mechanism includes an engaging member with one ormore ramped abutments 311 associated with each of the catch members 201,for lifting and halting forward movement of the catch members 201 duringan opening rotation of the drum, and one of more closing abutments 310associated with each of the catch members 201, for holding the catchmembers 201 captive during a closing rotation of the drum.

In the preferred form of the invention the drum engaging membercomprises a pivoting door or flap 300. The pivoting flap 300 includes apivot bar 301 along a rear edge which extends laterally as a pair ofcylindrical stubs 302 to engage within sockets of side housings 304 and305. A channel member 361 spans between the housings 304 and 305 and isconnected to the housings at its ends. The channel member 361 maintainsaccurate separation of the housings 304 and 305 and location of rotationbar 301 therebetween. The pivot bar 301 resides within an open channel362 of the channel member 361. The channel 362 supports the pivot rod301 along its length, reducing the stresses on stubs 302.

The flap 300 includes a leading face 315 spanning the width of the drumopening. The face 315 provides a barrier to entry into the space betweenthe drum and the housing when the flap 300 is in its engaging position.

The ramped abutments 311 are provided projecting from an inside facebacking on to leading face 315 and projecting toward the pivot bar 301.The ramped abutments take the form of teeth, tapering to a point spacedfrom the engaging member 300. Each tooth has an internal edge 3302 forreceiving the catch member 201 and an external edge 3304 for sliding onthe surface on the drum skin.

The flap 300 has a main connecting face 313 connecting between theinternal face and the pivot bar 301 across the width of the flap. Theclosing abutments 310 project from the face 313 and have abutment edges314 facing the ramped abutments 311. The projection of closing abutments310 from the face 313 is significantly less than the projection oframped abutments 311 from the face 313. In an opening operation theprojections 310 will clear the catch member 201 while the points oframped abutments 311 hook under the catch members 201.

The tracks 109 of drum 104 terminate at their forward ends 320 toprovide end faces against which the outward ends of catch members 201butt with the drum hatch 108 closed.

The T-shaped pivot arms 200 are raised to a drum opening position byriding up the ramped abutments 311 of drum engaging flap 300. Duringdrum opening the catch members 201 are raised clear of the end faces oftrack ends 320. After initiation of opening rotation of the drum withthe drum hatch held in place by the flap 300 the outer ends of catchmembers 201 reside above the outer surface of tracks 109. In thiscondition they are held between the outer surface of tracks 109 and theface 313 of flap 300. In a circumferential direction of the drum theyare blocked from movement in one direction by the ramped abutments 311and in the other direction by the closing abutments 310. During theopening rotation of the drum the catch members 201 will tend to bearagainst the ramped abutments 311.

During a closing rotation of the drum, as illustrated in FIG. 33A, thecatch members will tend to bear against the closing abutments 310. Oncethe drum hatch reaches a fully closed condition the catch members 201will fall off the outer surface of tracks 109 under influence of thespring members 230 and the closing abutments 310 will run clear abovethem. If the hatch cannot close due to obstruction (for example in FIG.33A) the catch member will remain trapped above tracks 109 and the doorwill remain coupled to the cabinet.

The flap 300 is moveable between an engaging position and a non-engagingposition. The effect of the drum engaging flap 300 in the engagingposition has been described above. In the non-engaging position the drumengaging flap 300 is pivoted to have its drum engaging end away from thesurface of the drum.

To assist with retention of the drum engaging flap 300 in a position topick up the catch members 201 during an opening sequence an arrangementis preferably provided for retaining the flap 300 close to the drum froma point shortly in advance of initial abutment with the catch members201 and then throughout subsequent opening and closing until the catchmembers 201 are released with the drum lid fully closed. Referring toFIG. 33A this retaining arrangement may take the form of a laterallyextending wing 3310 extending from each end of the flap 300 at alocation to engage within the respective track 109. To providepre-retention a short additional track section 3312 is provided on theoutside of the drum aligned with track 109. The short section of track3312 has an open end 3318 distal from track 109, for receiving entry ofwing 3310 at the beginning of an opening rotation. The end 3314 proximalto track 109 is separated from the end 320 of track 109 by catch memberreceiving notch 3316. Catch member 201 sits within notch 3316 when thehatch is fully closed. The wing 3310 is sufficiently long to span thenotch 3316 to ensure the flap 300 is not released as the wing passes thenotch.

Pivoting of the hatch engaging flap 300 can be described with particularreference to FIGS. 10 and 11. The flap 300 is pivotally supported bystub ends 302 of pivot bar 301 and along the length of the pivot bar bysupport rail 361. The flap 300 includes a lever member 330. The levermember 330 extends from the flap 300 adjacent one end of the engagingmember and from a point adjacent a pivot stub 302. An actuating rod 331has one end connected with the lever member 330 in a moment resistingrelationship. This connection may, for example, be by fitting within apre-moulded channel or by overmoulding. The rod 331 has a distal end 342that is moveable in a transverse direction (represented by arrows 346and 344) by an actuator mechanism. The preferred actuator mechanismrequires powered actuation in both movement directions.

The preferred actuation mechanism includes a worm drive gearbox with afirst gear 337 rotatable about a hub 350 and including outwardlyextending peripheral teeth 338. A drive gear 333 includes a spiralthread 334 engaged with teeth 338 of the first gear. The drive gear issupported between end support walls 336 and is driven by an electricmotor 332.

To absorb vibration a rubber spacer (not shown) may be provided underthe motor, lodged and compressed between the motor and the housing. Alsoto absorb vibration at least one of the ends of the drive gear 333 issupported within a resilient mounting in its respective support wall336. For example, as illustrated, the far end may be supported within abearing, such as in a seat or plastic bearing, with the bearing mountedwithin a rubber mounting board 360 fitted into an aperture in the wall336.

The first gear 337 and/or the drive gear are formed so that in operationtogether a positive stop action is provided at either end of a driveenvelope comprising less than a full turn of the first gear 337. Thepositive stop is provided by collision of drive gear structure withfirst gear structure when the first gear reaches either of its rotationlimits. One preferred combination of drive gear and first gearstructures is described below which absorbs the collision impact, butother structures are also envisaged to be within the scope of thisinvention. For example the spiral thread of the drive gear may have asquare end at either end of the spiral in the first gear may lackexpected teeth valleys at the requisite end stops. The square end of thespiral thread will collide against a respective face of the first gearwhen it reaches the unexpectedly missing valley.

Only a substantial proportion of the circumference of the first gear 337includes peripheral teeth 338. Adjacent each end of the toothed portionof first gear 337 is an outwardly placed collision member 339, 340. Thecollision members 339, 340 have a greater radial extent than theperipheral teeth 338. The collision members 339 and 340 are preferablyformed to provide flexibility adjacent the ends of the toothed portion338 of the first gear 337. For example, collision members 339 and 340preferably extend from the first gear 337 at a positioncircumferentially back from the toothed portion 338 of first gear 337and extending in a circumferential manner, spaced from but parallel theform of first gear 337, to end adjacent the ends of toothed portion 338.Thus the ends of the collision members 339 and 340 may deflect somewhatunder transverse pressure by flexing of the collision members.

Rotation of the first gear is stopped in either direction by collisionof the respective collision member 339 or 340 with the drive gear.Preferably the drive gear includes protrusions from its shaft atpositions displaced from the ends of spiral thread 334 and the collisionof collision members 399 and 340 is with the protrusions 335 rather thanwith the spiral thread 334. Preferably these protrusions are non-annularand extend as a transverse lugs. Movement of the first gear is halted bythe cessation of rotation of the drive gear on collision of the lugs 335with the tips of collision members 339 and 340.

Cessation of rotation of the drive gear while the electric motor 332 isenergised leads to a rapid and detectable increase in the motor current.The voltage applied to the motor may be removed upon detection of thisincrease in motor current although with some motor and power supplycombinations this may not be necessary. In the preferred form of theinvention the motor current is sensed by a one-bit digitisation circuit,as exceeding or not exceeding a threshold. An electronic controllerswitches off power supply to the motor as soon as the digitising circuitindicates the motor current has exceeded the threshold level.

Consequently the collision members 339 and 340 define the end limits ofmovement of the first gear 337. These end limits of movement aredepicted in FIGS. 10 and 11 respectively. Rotation of first gear 337 inthe direction of arrow 345 in FIG. 10 will, on completion of movement,lead to the position shown in FIG. 11. Rotation of first gear 337 in thedirection of arrow 343 in FIG. 11 will, on completion, lead to theposition to the FIG. 10.

A disc 341 is located in a circular aperture 351 in the body of firstgear 337 opposite collision members 339 and 340. Actuation rod 331extends through an aperture in a lug extending from disc 341. The lug isslidable along the collecting rod 331 and disc 341 is rotatable withinits aperture 351 in the first gear 337.

In rotation of the first gear from the position shown in FIG. 10 to theposition shown in FIG. 11 the disc 341 drags the distal end 342 of theactuation rod 331 from one side of hub 350 to the other in the directionof arrow 346. This rotates the actuation rod 331 about its end locatedin lever 330, thereby rotating lever 330 and hatch engaging flap 300about pivot stubs 302.

In the reverse movement of first gear 337, between the conditions inFIG. 11 and the condition in FIG. 10, the distal end 342 of connectingrod 331 is dragged in the direction of arrow 344, causing rotation ofthe hatch engaging flap 300 from its engaging position to itsnon-engaging position.

Controller

Referring to FIG. 12 the clothes drier of the present invention includesan electronic controller 900 programmed to control operations of themachine in response to user inputs and sensor input. The electroniccontroller is physically embodied as a PCB mounted electronics module139 in FIG. 1. In particular, the controller 900 controls the rotationalspeed and direction of the drum drive motor 902, energization in eitherdirection of the hatch engaging member door actuator motor 332,activation and deactivation of a lid lock solenoid 918 and activation ofa heater 930 (whether gas or electric element). The controller receivesuser inputs from user input panel 916, these inputs generally settingrequested drying cycle operating conditions (eg: start time, cycle time,requested dryness and operating temperature) and operative controls (eg:start, stop, pause and enter cool down mode). The controller 900receives additional inputs from current sensing circuit 906 sensingcurrent through lid lock solenoid (which indicates whether or not thelid is closed), moisture sensor 680, a current sensing circuit 914sensing the current through the motor 332, the output of a light sensor910, the output of a thermistor 912 indicating the temperature in thedrum, the output of a thermostat 932 detecting excessive temperature inthe drum, and any monitoring outputs of the installed heater unit.

General drying operation of the dryer will not be described in detail.Once the dryer is in an operating mode the preferred operating modeinvolves appropriate cycling of the drum rotation through sequences ofrotation in one direction with heat applied to incoming air followed bya briefer period of rotation in another direction without heat applied(or with heat applied at a lesser rate) generally for disentanglementproposes. In particular it is preferred that heat is only applied whenthe drive motor is driving the fan in its more efficient direction. Ifseparate drive motors are employed to drive the drum and drive the fanthen application of heat to the incoming air may be effected entirelyindependently of the drum rotation direction.

Moisture sensing of items in a drying load by resistance sensing betweena pair of conductive contacts is also known in the art and will not bedescribed in detail. Preferably the controller enters the dryer into acool down mode (where the drum is rotated and air flow applied withoutheat) when the sensed moisture content is less than or equal to amoisture content corresponding with the user selected level. It will beappreciated that other methods of detecting moisture content (forexample air outlet temperature profiles and air outlet moisture levels)may be used, and in all cases user selected moisture levels maycorrespond with raw or processed sensor levels rather than any absolutemoisture content. Lid locks and operation thereof in conjunction with alid sensing circuit are also well known in the art (particularly of toploading washing machines) and will not be described herein. Needless tosay the controller institutes a lock out on operation of the machine inthe absence of the sensor indicating the lid to be in a closedcondition, and maintains the lid lock in a locked condition throughoutoperation.

Preferred methods of operation of the dryer through drum opening anddrum closing operations, and through an initialisation procedure onpower up, form aspects of the present invention and accordingly thepreferred embodiment thereof will be described in detail with referenceto the Figures.

General Operations

The opening and closing operations of the dryer and an initialisationprocedure each include speed controlled operation of the drum to and/orfrom known rotational positions and actuation of the drum hatch engagingflap between retracted and extended positions.

Drum position is sensed via the light sensor 910. Referring inparticular to FIGS. 5 a and 5 b drum end 726 includes an annular arrayof dimples 950 pressed out of the face thereof. At least the peripheryof these dimples scatters light from the adjacent light sensor 910during rotation of the drum. The dimples 950 are regularly spaced apart,with a single dimple missing from its expected position in the annulararray. A position monitoring algorithm increments or decrements(depending on drum rotational direction) a drum position variable withthe passing of each dimple. A missing dimple detection loop checks forthe long unbroken signal indicating the missing dimple, incrementing ordecrementing the position variable to account for the missing dimple andusing this detection to reset the position variable when required.Position readings are therefore taken from the position from the missingdimple as datum, which is a known rotational position relative to theother physical features of the drum, such as opening and closing edgesof the drum opening.

It is not necessary that the controller monitor drum position throughoutnormal drying operation, as drum position may be re-established withinone full rotation of the drum when necessary for an opening operation.

The drum drive motor is preferably a standard AC induction motor. Thedrum drive motor speed is controlled for opening and closing operationsby chopping the applied AC voltage with a variable duty cycle to varythe effective applied AC voltage. The drum speed may be continuinglysensed via the light sensor. The periodic interruption of the receivedlight at the light sensor by the scattering of light from the drum enddimples is detected. The rate of interruption is directly proportionalto the drum speed in a known relationship. The controller determines therelationship between the drum speed and the required drum speed for theopening operation by monitoring this interruption rate and feedbackcontrols the chopping duty cycle to maintain the drum speed at or closeto the desired drum opening speed.

Alternatively the drum drive motor may be speed controlled by a variablefrequency inverter operating from a rectified power supply.

Where necessary the controller determines that the drum is stillrotating by the continued periodic interruption of the light sensorsignal. The timer detecting interruption intervals for the missingdimple detection loop also indicates a ceasing of drum rotation as soonas the elapsed time since the last signal interruption exceeds apredetermined threshold. The threshold may be a predetermined timeperiod or derived from previous interruption intervals.

For drum engaging flap actuation, operation of the actuator motor hasalready been described, including detection of end points by currentsensing of the actuator motor drive currents. In addition, duringactuation of the actuator drive motor the controller tracks the elapsedtime between initiating energisation of the actuator motor and the motorbecoming stalled. The controller routinely checks this elapsed timeagainst an expected range. An elapsed time outside the expected rangeindicates the possibility of incomplete activation of the hatch engagingflap.

Operation of Dryer through a Drum Opening Operation

The drum opening operation will be described with particular referenceto FIGS. 12 and 15 and the sequence of cross sections, FIGS. 6 to 9.

A drum opening operation is generally performed at the termination of adrying cycle. At the beginning of the drum opening operation the drum isgenerally rotating at operating speed. At step 1001, the controllerdetermines whether the drum is rotating in the door opening system. Ifthe drum is rotating forwards (anti-clockwise in FIG. 6) then at step1010 the controller halts rotation of the drum and restarts rotation inthe reverse direction (clockwise in FIG. 6). Once it is determined atstep 1001 that the drum is rotating in the correct direction then drumopening can begin.

At step 1002 the controller reduces the drum drive motor speed.Rotational speed is determined at step 1003, and further reduced at step1002 until the speed of the drum reaches a safe drum opening speed. Thecontroller then continues rotation at reduced speed until the loop ofsteps 1004 and 1005 determines that the drum has reached a rotationalposition that is a safe drum position for extending the drum hatchengaging flap. Preferably this position is set so the hatch engagingmember will reach full extension with the drum so that the drum is notrequired to rotate through more than a short distance at low speedbefore the drum hatch is engaged.

At step 1006 the controller energises the actuator motor 323 to rotatethe drum hatch engaging flap into its engaging position with theexternal edge of the ramped abutment teeth sliding on the surface of thedrum skin. At step 1007 the controller detects the moment when the firstgear arm 339 collides with the drive gear lug 335, by the increase incurrent in actuator motor 323. The controller times the interval betweenbeginning energisation at step 1006 and stalling of the actuator motorand determines at step 1007 whether the interval is within an expectedrange. If the interval is within the expected range the controllerde-energises the hatch engaging member motor at step 1009 and continueson its procedure. If the interval is outside an expected range thisindicates possibility of a fault and at step 1008 the controller eitherceases machine operation and indicates an alert or enters a recoveryroutine.

This extended position of the drum engaging flap is depicted in FIG. 7,immediately as the rotation of the drum has advanced the leading edge ofthe hatch to meet the ramped abutments of the drum hatch engaging flap.The leading points of the ramped abutment teeth slide under the catchmembers 201 of the T shaped pivoting arms by further rotation of thedrum until they are tucked up against the connecting face 313 of theflap. At this point no more forward movement of the catch members 201 ispossible relative to the hatch engaging flap and accordingly movement ofthe hatch is halted but the drum continues to rotate. The catch members201 riding up the edges of the ramped abutments also lifts the catchmembers from adjacent the drum surface. Further rotation of the drumrelative to the hatch brings the catch members 201 above the hatchholding side channels. The catch members 201 are thus maintained in apivoted out condition by the side channels while the drum is open orpartially open. As described with reference to FIG. 33A lateral wings ofthe drum engaging flap slot into the side channels 109 to retain andsupport the flap in position through the drum opening and closingoperations.

Referring again to FIG. 15, at a loop of steps 1011 and 1012 thecontroller continues to energise the drum drive motor to rotate the drumat the drum opening speed until such time as halting of rotation of thedrum is detected by the controller at step 1012.

The controller continues to monitor the rate of interruptions of thelight sensor signal to determine at step 1012 the instant when the drumceases rotation. The controller may also be configured with a currentsensing circuit to monitor the motor current to determine cessation ofmotor rotation by a rapid increase in motor current.

Rotation of the drum is eventually halted by an abutment on theunderside of the hatch engaging flap 300 coming to rest against ahalting abutment protruding from the outer surface of the side channel109.

As soon as the controller detects halting of rotation of the drum atstep 1012 it de-energises the drum drive motor. At step 1013 thecontroller determines whether the drum has reached a door fully openposition from its current drum position calculation. If it is thecontroller stops operation of the machine and disengages the lid lock atstep 1015. If the controller determines that the drum has not reached adoor open position then at step 1014 the controller stops operation ofthe machine and indicates an alert or enters a recovery mode.

The controller may apply a mechanical or electrical brake to maintainthe drum in its open position. The brake may for example compriseconnecting a substantial electrical resistance across the windings ofthe drum drive motor.

Operation of Dryer through a Drum Closing Operation

The drum closing operation is largely the reverse of the drum openingoperation. It will be described with reference to FIGS. 12 and 16 andthe sequence of cross sections 9 to 6.

Prior to closing the drum in a drum closing operation the controllerenergises the lid lock solenoid at step 1020 and confirms at step 1022that the lid lock has successfully activated. If the lid lock has notsuccessfully activated then the lid lock solenoid is de-energised atstep 1024 and a user alert is activated.

Once the lid lock has been successfully activated the closing operationproceeds to a drum slow closing loop comprising steps 1026, 1028 and1030.

At step 1026 the controller energises the drum drive motor to rotate thedrum in the drum closing direction at a drum closing speed.

The controller continues to energise the drum drive motor to rotate thedrum at the drum closing speed until the drum is past a door closedposition, detected at step 1030.

Between steps 1026 and 1030 in each loop the controller, determines thatthe drum is still rotating at step 1028. If it detects the drum hasstalled then the controller executes an error catching operation,beginning with halting rotation of the drum by de-energising the drummotor at step 1032. The controller then executes a drum opening loopcomprising steps 1034 and 1036. At step 1034 the controller energisesthe drive motor to rotate the drum in a door opening direction at a dooropening speed, detecting completion of the opening operation at step1036 by non rotation of the drum. Once the remedial drum openingoperation is completed operation of the machine is stopped at step 1038and a user alert is activated. Alternatively the controller may beconfigured to return to step 1026 and retry the closing operation.

Once it determines that it has reached the closed position at step 1030the controller energises the actuator motor 323 at step 1040, in areverse direction to withdraw the drum engaging flap to its disengagedposition. At step 1042 the controller detects stalling of the actuatormotor and compares the elapsed motor actuation time with an expectedrange. If the elapsed time is outside the expected range the controllerceases machine operation at step 1046 and activates a user alert.Alternatively the controller may be configured to initiate a recoveryoperation. If the elapsed time is within the expected range then at step1044 the controller de-energises motor 323 at step 1044. The controllerthen begins operation in a drying cycle at step 1048, includingaccelerating the drum to normal operating speed by ceasing chopping ofthe driving voltage of the drum drive motor.

Therefore in the drum closing operation the drum starts from rest and isrotated in a forward direction (anti-clockwise in FIG. 9) while thehatch is held stationary by the engaging flap. Rotation of the drumcontinues at the drum closing speed (preferably the same as the drumopening speed) until the leading edge of the vane forming the rear edgeof the drum opening reaches the leading edge of the drum hatch. As itdoes so the catch members 201 drops from the outer surface of the sidetracks at the notch adjacent the leading edge of the drum vane, drawn tothat position by the spring members 230. This releases the drum hatchfrom the drum hatch engaging flap. The drum hatch is secure from slidingfrom its closed position, in one direction by the catch members 201being unable to pass the ends of the side tracks, and in the otherdirection by the leading edge 182 being against the leading edge of thedrum vane.

If, as in FIG. 33A, anything is interposed in the opening during closingof the drum the catch members 201 do not reach the notch and thereforeremain on the outer surface of the side tracks and held by the closingabutments of the door 300. Accordingly the hatch remains coupled to thestationary cabinet and rotation of the drum is halted by abutmentagainst the hatch. The controller detects halting of the drum androtates the drum to reopen so that a user may remedy the situation.

Initialisation Procedure

Generally the controller is active even when the drying appliance is notoperating. In its soft powered down mode the controller continues toretain in memory a record of the current drum position and hatchengaging flap position. However these position records are lost if theappliance is hard powered down, for example due to a power supplyfailure or being switched off at the wall or being unplugged, includingon initial installation.

To establish correct status values for the appliance after a hard resetthe controller progresses through an initialisation procedure. Theinitialisation procedure is illustrated in FIG. 17.

The initialisation procedure begins with a drum closing operationsubstantially in accordance with steps 1020 to 1038 of FIG. 16.

In particular at step 1050 the controller energises the lid locksolenoid, and checks correct activation of the lid lock at step 1052,stopping operation and activating a user alert at step 1054 if the lidlock has not engaged. If the lid lock has properly engaged then thecontroller begins a drum closing loop of steps 1056, 1058 and 1060. Step1060 differs from step 1030 of the normal closing operation in that itdetects only that the drum has rotated a sufficient rotational angle tohave fully closed the door if the door had been fully open. If thecontroller detects at step 1058 that the drum has stalled, beforedetermining at step 1060 that the drum has rotated a sufficient angle tohave closed the door, then it halts rotation of the drum at step 1062and initiates a drum opening loop of steps 1064 and 1066. It initiatesrotation of the drum in a door opening direction in step 1064 untildetermining the drum as stalled at step 1066 at which time it stopsmachine operation and activates a user alert at step 1068.

If the controller determines at step 1060 that the drum has rotatedsufficient distance to have closed the door then at step 1070 thecontroller de-energises the drum drive motor at step 1070. Theassumption is made that the drum is now in a closed conditionirrespective of its starting condition.

At step 1072 the controller energises the hatch engaging flap actuatormotor in a rotational direction to retract the hatch engaging flap. Atstep 1074 the controller determines if the actuator drive motor stallswithin a short period, essentially instantly, and if so proceeds to asub routine of steps 1076 to 1088.

If the motor did not stall instantly then at step 1090 the controllerdetermines whether the actuator motor stalls within a present maximumtime. If not then at step 1092 the controller stops operation of themachine and activates a user alert. If the actuator motor has stalledwithin a maximum time then at step 1094 the controller stopsenergisation of the actuator motor and re-energises the actuator motorin a direction to advance the drum hatch engaging flap. At step 1096 thecontroller determines whether actuator motor stalls within an expectedelapsed time range, if not proceeding to step 1098, stopping machineoperation activating a user alert. If the controller determines at step1096 that the hatch engaging member motor has stalled with the elapsedtime within the expected range then at step 1100 the controller stopsenergisation of the actuator motor, and re-energises the actuator motorin a direction to retract the drum hatch engaging flap, detecting atstep 1102 whether the actuator motor stalls with an elapsed time withinthe expected range. If the controller detects at step 1102 that theelapsed time is outside the expected range then at step 1104 thecontroller stops operation of the machine and activates a user alert.Otherwise at step 1106 the controller commences an opening operation inaccordance with FIG. 15.

If at step 1074 the controller determines that upon initial energisationthe actuator motor stalled instantly, then at step 1076 the controllerstops energisation of the actuator motor and re-energises the actuatormotor in a direction to advance the drum hatch engaging flap. Thecontroller determines at step 1078 whether the elapsed time betweenenergising the actuator motor at step 1076 and the motor stalling fallswithin an expected range. If not, the controller stops operation of themachine at step 1080 and actuates an user alert. If at step 1078 theelapsed time was within the expected range then at step 1082 thecontroller stops energisation of the actuator motor and re-energises theactuator motor in a direction to retract the drum hatch engaging flap.At step 1084 the controller determines whether the elapsed time betweenenergising the actuator motor at step 1082 and the motor stalling iswithin an expected range. If not then at step 1086 the controller stopsoperation of the machine and activates a user alert. Otherwise at step1088 the controller de-energises the actuator motor, and commences adrying procedure including energising the drum drive motor at a normaloperating speed. Automatically commencing a drying operation if theinitialisation process indicated a closed drum position with hatchengaging member retracted may be a user option set in non volatilememory. It is a useful option which ensures that operations interruptedby power cut are completed without user intervention.

1. A clothes drying appliance comprising: a base structure, a drum,having at least one drum end, and an aperture forming an air outlet ofsaid drum in said drum end, a drum support structure supporting saiddrum for rotation, a movement interface between said drum supportstructure and said base structure, an outlet duct supported on said drumsupport structure and having an inlet end sealingly connected with saidair outlet of said drum, and an outlet end, said outlet duct stationarywhen said drum is rotating, in use air drawn from inside said drumthrough said air outlet and into said inlet end, and an exhaust ductconnected with said base structure, said exhaust duct having an outletport outside said base structure and an inlet port, said drum supportstructure, said drum and said outlet duct movable between an operatingposition on said base structure, and a maintenance position where saiddrum, said drum support structure and said outlet duct are moved forwardfrom said base structure, said movement interface adapted to move saiddrum support structure, said drum and said outlet duct between saidoperating position and said maintenance condition, said outlet end ofsaid outlet duct positioned to sealingly mate with said inlet port ofsaid exhaust duct with said drum support structure in said operatingposition.
 2. A clothes drying appliance as claimed in claim 1 whereinsaid base structure is a cabinet or surround structure.
 3. A clothesdrying appliance as claimed in claim 1 wherein said drum supportstructure pivots about a forward lower edge of said base structure andsaid exhaust duct is located adjacent the rear lower edge of said basestructure.
 4. A clothes drying appliance as claimed in claim 3 whereinsaid outlet duct includes a fan housing adjacent said outlet end and anoutlet of said fan housing is positioned on said inlet port of saidexhaust duct at least in said operating position.
 5. A clothes dryingappliance as claimed in claim 1 wherein at least one of said outlet ductand said exhaust duet include a peripheral flange portion for buttingagainst a flange or end face of the other said duct.
 6. A clothes dryingappliance as claimed in claim 5 wherein at least one of said peripheralflange portion and said flange or end face includes a soft or resilientsealing layer thereon.
 7. A clothes drying appliance as claimed in claim5 wherein said outlet duct includes an upstand wall around at least alower part of said outlet end, said upstand wall dimensioned andpositioned to fit within said exhaust duct inlet port with movement ofsaid drum support structure into said operating position.
 8. A clothesdrying appliance as claimed in claim 5 wherein said exhaust ductincludes an upstand wall extending from around at least the upperportion thereof and dimensioned and positioned to extend into the saidoutlet end of said outlet duct with said drum support structure movedinto said operating position.
 9. A clothes drying appliance as claimedin claim 8 wherein said upstand wall of said exhaust duct and saidupstand wall of said outlet duct together encompass the entire perimeterof the mated openings, providing an interleaved connection therebetweenaround said perimeter.
 10. A clothes drying appliance as claimed inclaim 5 wherein said exhaust duct includes an upstand wall extendingfrom around at least the upper portion thereof and dimensioned andpositioned to extend into said outlet end of said outlet duct with saiddrum support structure moved into said operating position.
 11. A clothesdrying appliance as claimed in claim 1 wherein said drum supportstructure includes at least a pair of horizontally extending and spacedapart parallel connecting members, and a motor drive support memberconnected along one side with a first one of said pair of parallelconnecting members and along another side with a second one of said pairof parallel connecting member.
 12. A clothes drying appliance as claimedin claim 11 wherein said motor drive support member includes a firsthalf fan housing, and said clothes drying appliance also includes asecond half fan housing is connected with said first half fan housing toprovide a complete fan housing with an air inlet opening at one sideconnected with, and forming part of, said outlet duct in use, and a fanshaft opening at its other side.
 13. A clothes drying appliance asclaimed in claim 12 wherein said motor drive support member includes amotor well defined at least in part by a pair of end walls, each saidend wall including a bearing receiving recess, one said end wall forminga side wall portion of said first half of said fan housing.
 14. Aclothes drying appliance as claimed in claim 13 wherein said clothesdrying appliance further comprises a motor mounted in said motor well,and motor includes a drive shaft extending from each end thereof beyondsaid end walls, one said end projecting into said fan housing and theother said end including a main drum drive pulley mounted thereon.
 15. Aclothes drying appliance as claimed in claim 14 wherein said applianceincludes a belt tensioning device including a yoke extending around saiddrive pulley, a support for said yoke which enables pivoting and slidingmovement of said yoke in relation to said drive pulley, a pair of spacedapart tensioning pulleys, each having an axis of rotation substantiallyparallel with the axis of rotation of said drive pulley, with the linebetween the centres of said tensioning pulleys separating said drivepulley from said drum, said tensioning pulleys spaced sufficiently closeto impinge upon the path of a belt which passes around said pulley andsaid drum, and a biasing agent pressing said pulleys toward said drum.